I would not wait.
This is a textbook “patient safety + material disclosure” crisis. The right move is rapid, documented, regulator-first action.

Immediate stance (set at Hour 0)

1. Patient safety first (interim risk controls now, not after perfect certainty).
2. Regulator-first transparency (early notification before formal package is complete).
3. No selective disclosure (align with securities law/Reg FD).
4. Single source of truth (war room, written decision log, one spokesperson).

---

48-hour action plan (hour-by-hour)

Hour	Action	Why
0	Activate crisis command center (CEO-led)	Centralized control prevents delay/confusion.
1	Freeze non-essential decisions; issue legal hold	Preserves evidence, reduces litigation risk.
2	Bring in outside FDA counsel + product liability counsel	Independence and privilege on sensitive work.
3	Convene CMO, Safety, Biostats, Regulatory, GC, CFO, IR, Comms	Cross-functional decisions needed immediately.
4	Validate internal signal dataset (case definitions, confounders)	Avoid acting on bad analytics while moving fast.
5	Quantify impact: expected liver-failure cases by cohort/region	Gives risk context for regulators and board.
6	Draft interim medical policy: pause new starts pending review; no abrupt discontinuation for current patients	Protects patients without triggering unsafe stoppage.
7	Suspend all DTC marketing, speaker programs, sales incentives for drug	Ethical and legal optics; reduces exposure.
8	Brief Board Chair and Lead Independent Director 1:1	No surprises; prepares governance support.
9	Form Independent Safety Review Panel (hepatology + pharmacoepi experts)	Credible external validation for regulators/public.
10	Start draft “Dear HCP” safety communication and patient FAQ	Fast clinician guidance is critical.
11	Regulatory team prepares expedited safety signal notification (FDA/EMA/etc.)	Demonstrates good-faith compliance.
12	Notify FDA/major regulators of emerging serious risk signal; request urgent meeting	Relationship trust and reduced enforcement risk.
13	Build decision tree: label update vs boxed warning vs temporary restricted use	Board needs concrete options.
14	Launch adverse-event deep dive (all global safety databases + literature)	Strengthens signal and defensibility.
15	Stand up patient hotline staffing plan (medical affairs + nurses)	Patient safety and reputational containment.
16	Draft internal employee note (facts, values, confidentiality, escalation channel)	Stabilizes morale and prevents rumor spiral.
17	CFO builds financial scenarios (base, severe, withdrawal) and liquidity plan	Protects enterprise continuity.
18	IR + GC prepare materiality memo for disclosure committee	Determines timing/content of market disclosure.
19	Prepare voluntary field guidance to prescribers: baseline/periodic LFT monitoring	Immediate harm reduction for current patients.
20	Quality/Manufacturing checks for lot signal (rule out CMC contribution)	Could change root cause and corrective actions.
21	Align global affiliates on single protocol and message	Avoids contradictory country actions.
22	Finalize board pre-read package (data, options, legal, financial, comms)	Enables informed board decision in 48h meeting.
23	Rehearse crisis media Q&A (CEO/CMO only spokespeople)	Reduces misstatements and liability.
24	Hold emergency board committee call (Audit + Risk + Safety)	Governance record of prompt oversight.
25	Decide preliminary external posture: “new serious risk identified; actions underway”	Transparency before rumors/leaks.
26	Prepare draft 8-K / equivalent disclosure documents	Material event likely; must avoid delayed disclosure.
27	Pre-brief top 20 payer/health-system partners under controlled legal process	Prevents chaotic formulary reactions.
28	Finalize HCP letter content pending regulator feedback	Speed to clinician action.
29	Confirm sales force stand-down script (“no promotion; direct to medical info”)	Cuts legal exposure from off-message field talk.
30	Internal leadership town hall (VP+ level)	Retains trust, prevents attrition panic.
31	Execute hotline launch, website safety page, pharmacovigilance intake surge plan	Operational readiness for disclosure day.
32	Conduct second regulator touchpoint; share updated analyses	Shows continuous cooperation.
33	Decide on earnings call structure: move guidance to “under review”	Avoids misleading forward-looking statements.
34	Final legal review: wording for patients (“do not stop without physician”)	Prevents unintended clinical harm.
35	Simulate first 24h post-disclosure media/social response and escalation triggers	Faster, calmer incident response.
36	Issue controlled public disclosure (if materiality threshold met): press release + filing	Legal compliance and credibility.
37	Release HCP communication through medical channels	Clinicians act before media confusion spreads.
38	Activate outbound calls to major prescriber groups and patient advocates	Trust-building and harm reduction.
39	Start daily safety dashboard (new cases, calls, script trends, sentiment)	Data-driven steering.
40	Finalize board deck with post-disclosure metrics and next-step asks	Board decisions need fresh info.
41	Prepare board resolutions: label change filing, risk program, comp clawback review if needed	Demonstrates accountability and control.
42	Meet with board members who favored delay; walk through liability and ethics case	Aligns governance, reduces internal fracture.
43	Formal board meeting: vote on full action package	Secures mandate and record.
44	Immediately execute board-approved actions (regulatory submissions, monitoring program)	No lag between decision and action.
45	Finalize earnings call script: safety first, facts known/unknown, financial range withdrawn/reframed	Credible investor communication.
46	Media and employee update after board meeting	Keeps narratives consistent internally/externally.
47	Set 7-day plan: additional data cutoff, regulator meeting dates, independent review publication	Shows momentum beyond crisis day.
48	CEO readiness review for earnings call and regulator follow-ups	Tight final alignment before public scrutiny.

---

Why this is the right approach

• Legal liability: Early regulator notice + documented action reduces punitive exposure versus “wait and see.”
• Ethics/patient safety: Immediate mitigation (pause new starts, clinician guidance, monitoring) can prevent avoidable liver failures.
• Financial: Stock hit is likely either way; delay risks a larger collapse plus enforcement/settlement costs.
• PR: Candor + empathy outperforms defensiveness. “We found it, we acted fast” is survivable.
• Employee morale: Clear internal communication prevents fear and rumor-driven attrition.
• Regulatory relationships: Proactive transparency buys credibility for future interactions.

If you want, I can also draft the board opening statement and a 3-minute earnings-call script aligned to this plan.